1. Field of the Invention
The field of the present invention relates to flashlights and flashlight components.
2. Background
Various flashlight designs are known in the art. Flashlights typically include one or more dry cell batteries. In certain designs, the batteries are arranged in series in a battery compartment of a barrel or tube that acts as a handle for the flashlight. An electrical circuit is frequently established from one electrode of the battery or batteries through a conductor to a switch, then through a conductor to one electrode of the lamp bulb. After passing through the filament of the lamp bulb, the electric circuit emerges through a second electrode of the lamp bulb in electrical contact with a conductor, which in turn is in electrical contact with the other electrode of the battery or batteries. Actuation of the switch to complete the electric circuit enables electricity to pass through the filament, thereby generating light which is typically focused by a reflector to form a beam of light.
The production of light from such flashlights has often been degraded by the quality of the reflector used and the optical characteristics of any lens interposed in the beam path. As a result, efforts at improving such flashlights have often attempted to address the quality of their optical characteristics. For example, more highly reflective, well-defined reflectors have been found to provide a better-defined focus thereby enhancing the quality of the light beam produced. Additionally, several advances have been achieved in the light emitting characteristics of flashlight lamp bulbs.
Despite such efforts, light beams produced by known flashlights are frequently elliptical or elongated in shape. These aberrations generally result from the fact that the flashlight lamp bulb is not properly aligned with the principal axis of the reflector of the assembled flashlight.
In various flashlight designs, the lamp is supported within the flashlight by a holder or spacer within the barrel and extends into the flashlight reflector. Due to manufacturing and assembly operations and tolerances, however, after manufacture of the flashlight is fully completed, the lamp may be permanently misaligned with the reflector, resulting in degraded performance. Furthermore, simply locating the center of the lamp bulb on the principal axis of the reflector does not ensure that aberrations in the projected light beam will be eliminated. This is because the critical component of the lamp that must be centered relative to the reflector is the lamp filament.
One attempt at addressing the misalignment problem is described in U.S. Pat. No. 5,260,858, by A. Maglica. This patent describes a flashlight that includes a switch housing that partially floats within the barrel of the flashlight to allow for slight movement of the lamp relative to the reflector, thereby helping to ensure that the lamp and the lamp filament are centered relative to the reflector. However, in the centering mechanism described in U.S. Pat. No. 5,260,858, to the extent that the lamp filament is not centered within the bulb, then the lamp filament will not be properly centered within the reflector and optimal performance of the flashlight will not be achieved.
Switch designs that are adapted to close an electrical path between the lamp bulb and battery, or batteries, in response to axial movement of the head along the barrel and to open the electrical path in response to axial movement in the opposite direction along the barrel are known. While such switches have generally worked well for flashlights that employ smaller batteries of the AA or AAA type, known designs are not well suited for flashlights that employ larger battery sizes, such as C or D size batteries. One reason such designs are not well suited for flashlights employing larger batteries is that the positive electrode of the battery closest to the head end of the flashlight is urged against a conductor mounted flush against the bottom of the switch. As a result, the battery or batteries may become damaged in the event that the flashlight is dropped. The problem also becomes more acute as the number of batteries connected in series increases due to the added weight, and hence momentum, of the batteries. Another reason such switch designs are not well suited for flashlights with larger batteries is that they are not designed to handle the heat associated with higher amperage lamp bulbs rated for use with such batteries.
Current switch designs that open and close in response to axial movement of the head assembly along the barrel are also not designed to ensure that the filament of each bulb will always be properly aligned with the principal axis of the reflector. As a result, optimal performance of such flashlights is not always achieved.
Misalignment problems are likely to be more pronounced in flashlights with higher capacity bulbs, because such bulbs tend to be longer, thus accentuating any misalignment between the bulb holding mechanism of the flashlight and the reflector as well as any misalignment of the bulb filament within the bulb itself.
The development of flashlights having a variable focus, which produces a beam of light having variable dispersion, has also been accomplished. In such flashlights, the head assembly is typically rotatably connected to the barrel of the flashlight at the end where the bulb is retained. In addition, the head assembly is adapted to be controllably translatable along the barrel such that the relative positional relationship between the reflector and lamp bulb may be varied, thereby varying the dispersion of the light beam emanating through the lens from the lamb bulb. While variable focus flashlights have also employed switches that are adapted to open and close in response to the axial movement of the head assembly, such flashlights have generally been limited to flashlights employing AA and AAA batteries for a variety of reasons, including some of those described above.
In metal flashlights, the flashlight""s tail cap is typically a component of the electrical circuit and there must be electrical continuity from one part of the tail cap to another, usually from an outer peripheral region to an inner peripheral region. In such designs when the tail cap and the barrel are anodized, painted, or otherwise treated so that the surface of the tail cap or the barrel loses all or a part of its ability to conduct current, then extra processing steps are required to either remove the non-conducting coating from electrical contact points or mask the contact points prior to forming the coating.
In order to avoid having to remove the nonconductive coating from the contact points of the tail cap, or mask the contact points, attempts have been made to eliminate the tail cap from the electrical circuit. Several different designs have been employed to achieve this end. Such designs, however, have required the use of a plurality of parts and multiple manufacturing steps. The elimination of any such parts and steps would decrease the overall manufacturing cost of the flashlight, as well as improve the reliability of the flashlight.
It is an object of the present invention to address or at least ameliorate one or more of the problems associated with the prior art noted above.
Accordingly, in a first aspect of the present invention, it is an object to provide a device that may be used to align the filament of a lamp bulb with a reflector, particularly flashlight reflectors, although the invention is not limited to flashlight reflectors.
In accordance with this object, in a first aspect of the present invention a combination for use in aligning a flashlight lamp bulb with the principle axis of a flashlight reflector is provided. The combination includes a lamp bulb and a lamp base. The lamp bulb has a pair of electrodes and a filament extending between the electrodes. The lamp base is adapted to receive the electrodes of the lamp bulb. The lamp bulb is secured to the base so that the electrodes extend through the base, the lamp bulb is disposed adjacent the base, and the filament of the lamp bulb is aligned with a predetermined axis extending through the base. The base is configured to be seated in a bore provided in a base receiver mounted adjacent to a forward end of the flashlight so as to align the predetermined axis of the base with the principal axis of the reflector.
In accordance with the first aspect of the present invention, a combination for use in aligning the filament of a lamp bulb with the principle axis of a reflector is also provided. The combination comprises a bi-pin lamp bulb and a lamp base. The lamp bulb has a bulb portion, a pair of electrodes and a filament extending between the electrodes. The lamp base comprises a conical frustum having a circular base end, a circular truncated end parallel to and concentric with the base end, and a conical-shaped side wall interposed between the two. The lamp base further includes two holes extending through the base in a direction parallel to an axis extending through the center of the base end and truncated end and adapted to receive the electrodes of the lamp bulb. The lamp bulb is secured to the base so that the electrodes extend through the base, the bulb portion is disposed adjacent the base, and the filament of the lamp bulb is aligned with the axis.
In yet another embodiment of the first aspect of the invention, a combination is provided that comprises a lamp bulb, a lamp base, a reflector, and a lamp base receiver. The lamp bulb includes a pair of electrodes and a filament extending between the electrodes. The lamp bulb is secured to the lamp base so that the center of the filament is aligned with a predetermined axis of the lamp base. The lamp base is adapted to receive the lamp base receiver and align the predetermined axis of the lamp base with the principal axis of the reflector.
The lamp base may include a tapered surface concentric about the predetermined axis, and the tapered surface may be seated against a matching tapered surface provided in the lamp base receiver that is concentric about the principal axis of the reflector.
In another aspect of the invention, a method of manufacturing a lamp bulb and lamp base combination is provided. The method comprises the steps of first obtaining a lamp bulb having a bulb portion, a pair of electrodes extending from the bulb portion, and a filament extending between the electrodes within the bulb portion. The lamp bulb is then inserted into a lamp base adapted to receive the electrodes of the lamp bulb until the bulb portion of the lamp bulb is adjacent the base and the electrodes extend through the base. The lamp base is adapted to permit lateral movement of the bulb portion and electrodes with respect to a predetermined axis extending through the lamp base. The lamp bulb is then laterally adjusted with respect to the predetermined axis of the base until the filament of the lamp bulb is aligned with the predetermined axis. The lamp bulb is then secured to the lamp base to preserve the alignment of the filament with the predetermined axis.
In yet another aspect of the invention it is an object to provide a flashlight with improved optical characteristics. The flashlight includes a barrel for retaining one or more batteries. A head assembly is mounted to a first end of the barrel. The head assembly includes a lens and a reflector having a central opening surrounding the principal axis of the reflector. A lamp bulb having a filament extending between two electrodes is secured to a lamp base so that the lamp bulb is disposed adjacent the base and the filament of the lamp bulb is aligned with a predetermined axis extending through the base. A lamp base receiver is mounted adjacent the first end of the barrel. The lamp base is removably seated in a complementary bore extending through the lamp base receiver, and the lamp base receiver is mounted adjacent the first end of the barrel so that the lamp bulb extends through the central opening in the reflector and the predetermined axis of the lamp base is aligned with the principal axis of the reflector. A tail cap is attached to the second end of the barrel. An electrical circuit couples the electrodes of the lamp bulb to the one or more batteries. A switch is interposed in the electrical circuit for turning the flashlight on and off.
In still another aspect of the invention, it is an object to provide a new tail cap assembly for a flashlight having a barrel with a forward end and a rearward end. The tail cap assembly comprises a tail cap comprising a first body portion having a first end and a second end and being adapted to removably engage the interior of the flashlight barrel at the rearward end. A second body portion is attached to the second end of the first body portion and is adapted to enclose the rearward end of the flashlight barrel when the first body portion engages the barrel. A spring seat is provided at the first end of the first body portion, and may comprise a pair of spaced apart, opposing ears, with opposing gaps provided at the ends of the opposing ears. The tail cap assembly further includes a conductive spring that includes a base portion removably retained between the opposing ears of the spring seat. The base portion is adapted to extend outward in a radial direction through the opposing gaps provided between the ears so as to make physical contact with the inner surface of the barrel when the tail cap is engaged with the barrel.
In still another aspect of the invention, it is an object of the invention to provide a new design for a flashlight that does not require the tail cap to be included in the electrical circuit. The flashlight includes a barrel for retaining a battery source of power and having first and second ends. The barrel further comprises an electrically conductive material. A bulb is positioned at the first end of the barrel. A tail cap is removably engaged with the interior of the second end of the barrel. The tail cap includes a spring seat positioned on the interior of the barrel. The spring seat comprises a pair of opposing ears spaced apart from the axis of the barrel. A conductive spring is disposed between the tail cap and a case electrode of the battery source of power. The conductive spring includes a base portion removably retained between the opposing ears of the spring seat and which is adapted to extend outward in a radial direction through opposing gaps provided between the ears so as to make physical contact with the inner surface of the barrel when the tail cap is engaged with the barrel. In addition, the spring serves to provide a direct electrical path between the case electrode of the battery source of power and the barrel. The flashlight further comprises an electrical circuit coupling the bulb to the battery source of power that includes the direct electrical path provided by the spring between the case electrode and barrel. A switch is interposed in the electrical circuit to turn the flashlight on and off.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments.